In the environment of railroad cars, it is generally necessary to provide on-board electric power to electronic devices such as electronically controlled pneumatic (EPC) brakes, on-board monitoring devices, and other similar devices on a freight car, particularly if they are wireless systems. At this time, all of the proposed or installed systems have batteries charged from an on-board generator to supply power. A problem arises when the freight cars are not in use and they sit for several months. The batteries may lose their charge over time and need to be replaced or recharged before operating the freight car. In colder climates, this problem becomes worse since the batteries lose their charge delivering capacity faster at lower temperatures. For safety purposes, it is desirable to have the brakes of a rail car 100% operational before the train leaves the station. With a wireless ECP brake communication system, the on-board equipment cannot be charged by a head end unit (HEU) or by the generator in a stationary freight car.
Another problem with the currently planned and employed on-board charging system is that it relies on axle generators. The axle generator provides a voltage proportional to the train speed and it is very difficult and expensive to achieve sufficient voltage, usually at least 12V, at low speeds such as five to ten km/hour. Also, the voltage regulation at high speeds, where the voltage can reach well over 150V, can be costly and pose a technical challenge.